Who will make the finals? The wisdom of crowds

It’s hard to make predictions, especially about the future, or so the cliche goes. It’s easy to point out silly calls after the fact, but harder to put your name to a clear prediction. I’m grateful to the 92 of you who put your name to predictions about which AFL teams will make the finals in 2017.

Predictions compared

Entrants to the finalists-tipping competition are very sure that the GWS Giants will make the finals, with good reason. The median estimate was that the Giants have an 88.4% shot at the finals this year. That’s more bullish than the chances given to the Giants by the betting markets (79%) or our Elo model (72.8%). At the other end of the scale, the clear consensus is that the Lions have a tiny chance of making it. Betting markets give them a 6.1% shot, our Elo model puts it at 3.7%, while the median estimate from competition estimates is 1.3%.

Competition entrants are more certain than the betting markets about the likely finalists. The median competition entrant gives favourites like the Giants and Swans a better chance of making the finals than the markets, while cellar dwellers like the Suns are rated a better shot by the markets than they are by competition entrants.

THE ROOS: EVEN LESS PREDICTABLE THAN ESSENDON

Competition entrants are nearly unanimous about the Lions’ slim chances at making the finals this year. The 25th percentile estimate for their finals chances is 0%, while the 75th percentile is 5%. That five percentage point range is the lowest of any team – the crowd is more certain about the Lions’ fate than they are about any other team. North Melbourne and Essendon, on the other hand, are the league’s biggest question markets. There’s a whopping 33.8 percentage points between the 25th and 75th percentile estimates for the Kangaroos’ chances of making the finals, the biggest of the league. The Bombers aren’t far behind – competition entrants are justifiably split on Essendon’s chances of making the finals after regaining half their squad from suspensions.

You can see that the distribution of estimated finals probabilities for Essendon and North Melbourne is flat – there are a wide range of opinions about their chances of making the finals. Collingwood and Fremantle also divide opinion, with a broad range of estimates of their finals chances.

The Lions break the scale . Competition entrants are so unanimous about Brisbane’s near-zero chance of making the finals that their distribution can’t be fit on the same scale as the other teams.

What will be obvious with the benefit of hindsight is not at all obvious in February. Some of these predictions will look silly in a few months time. Thanks to everyone who lodged a prediction and risked looking silly.

NOTE ABOUT COMPETITION ENTRIES

Not everyone’s probabilities added up to 800. In those cases, I’ve scaled the predictions up or down. For example, if your probabilities added to 1000, they’ve all been multiplied by 0.8. These scaled probabilities will be used to calculate who wins.